How severe is CVE-2011-1901?

CVE-2011-1901 has a CVSS 2.0 base score of 7.5, rated high severity.

Is CVE-2011-1901 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-1901?

CVE-2011-1901 primarily affects Proofpoint Messaging Security Gateway. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-1901?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2011-1901 published?

CVE-2011-1901 was published on 2011-05-05 and last updated on 2026-06-16.

CVE-2011-1901

CVE-2011-1901 is a high-severity vulnerability in Proofpoint Messaging Security Gateway with a CVSS 2.0 base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: High (CVSS 2.0 base score 7.5)
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Proofpoint Messaging Security Gateway
Published: 2011-05-05
Last modified: 2026-06-16

Description

The mail-filter web interface in Proofpoint Messaging Security Gateway 6.2.0.263:6.2.0.237 and earlier in Proofpoint Protection Server 5.5.3, 5.5.4, 5.5.5, 6.0.2, 6.1.1, and 6.2.0 allows remote attackers to bypass authentication via unspecified vectors.

Frequently asked questions

What is CVE-2011-1901?: The mail-filter web interface in Proofpoint Messaging Security Gateway 6.2.0.263:6.2.0.237 and earlier in Proofpoint Protection Server 5.5.3, 5.5.4, 5.5.5, 6.0.2, 6.1.1, and 6.2.0 allows remote attackers to bypass authentication via unspecified vectors.
How severe is CVE-2011-1901?: CVE-2011-1901 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2011-1901 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-1901?: CVE-2011-1901 primarily affects Proofpoint Messaging Security Gateway. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-1901?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2011-1901 published?: CVE-2011-1901 was published on 2011-05-05 and last updated on 2026-06-16.

References

Affected products (7)

cpe:2.3:a:proofpoint:messaging_security_gateway:*:*:*:*:*:*:*:*
cpe:2.3:a:proofpoint:protection_server:5.5.3:*:*:*:*:*:*:*
cpe:2.3:a:proofpoint:protection_server:5.5.4:*:*:*:*:*:*:*
cpe:2.3:a:proofpoint:protection_server:5.5.5:*:*:*:*:*:*:*
cpe:2.3:a:proofpoint:protection_server:6.0.2:*:*:*:*:*:*:*
cpe:2.3:a:proofpoint:protection_server:6.1.1:*:*:*:*:*:*:*
cpe:2.3:a:proofpoint:protection_server:6.2.0:*:*:*:*:*:*:*

More vulnerabilities in Proofpoint Messaging Security Gateway

CVE-2011-1904 — High (CVSS 7.5): An unspecified function in the web interface in Proofpoint Messaging Security Gateway 6.2.0.263:6.2.0.237 and earlier…
CVE-2011-1903 — High (CVSS 7.5): SQL injection vulnerability in an unspecified function in Proofpoint Messaging Security Gateway 6.2.0.263:6.2.0.237 and…
CVE-2011-1905 — Medium (CVSS 6.8): Multiple cross-site request forgery (CSRF) vulnerabilities in unspecified administrative modules in Proofpoint…
CVE-2011-1902 — Medium (CVSS 5.0): Directory traversal vulnerability in the web interface in Proofpoint Messaging Security Gateway 6.2.0.263:6.2.0.237 and…

All CVEs affecting Proofpoint Messaging Security Gateway →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →